Fliers were put up throughout the community and area schools were notified of the device, which was initially described by the Army as volatile and dangerous enough to cause serious injury.

The device resembles a flare but is yellow and about 9 inches long. It has a serial number printed on it and the brand name "Dyno Nobel." It does not have a fuse, however.

Anyone who finds it is urged not to touch it and to immediately call 911.

The device had been placed under a car in an impound lot on Schofield Barracks but no one told the owner, who drove about five miles without knowing the device was there.

The device was lost somewhere between Schofield Barracks' Foote Gate and a gas station on California Avenue in Wahiawa.

More than 200 soldiers working in six different search parties were involved today, said Master Sgt. Patty Winebrenner, a spokeswoman for the 25th Infantry Division (Light) and U.S. Army Ha-wai'i.

"They are using all sorts of different methods," she said. "They are using buckets to scoop through water to see if there is anything there and they are using rakes to go through loose dirt."

Soldiers also checked under parked cars and into storm drains.

Winebrenner was not sure exactly how dangerous the device was.

"It is a device that is used to train military working dogs the world over," Winebrenner said. "None of us are experts on this when it comes to what it is. It is an explosive device and we are treating it as a dangerous device."

The soldiers who lost the device yesterday followed all regulations for the training exercise, she said.

Col. Arnaldo Claudio, provost marshal for U.S. Army, Hawai'i, initially said the device was "inadvertently" left under a vehicle yesterday afternoon but later said it was deliberately put there for training.

Claudio likened the circumstances of the device's disappearance to "Murphy's Law."

The device emits an odor that bomb-sniffing dogs are trained to find. Yesterday afternoon, soldiers hid one of those devices in the undercarriage of a car in a Schofield impound lot, between the muffler and tailpipe, for the dogs to find, Claudio said.

But a man showed up to claim the car and drove off.

The training personnel were more than 100 yards away, and the car was gone before anyone realized it was the target vehicle, Claudio said.

More than 280 cars were in the lot.

"You have all these hundreds of cars and the car that this device is put into belongs to the only guy that that day was going to take the car outside of the impound lot," Claudio said.

Army personnel reached the man by cellular phone. He drove back to the base. MPs searched the car, but the device was gone.

The vehicle had traveled about five miles. It left Schofield's Foote Gate on Kunia Road, drove onto Wilikina Drive to Kamehameha Highway, turned onto California Avenue then North Cane Road, where it made a right to the police station, Honolulu Assistant Police Chief Boisse Correa said. Police joined the search.

The device was reported missing at 3:30 p.m. Last night's search involved 170 Army personnel and the police Specialized Services Division.

Claudio said the device contains chemicals "that if played with or if there is any friction or change in temperature to it, it could explode and hurt somebody pretty seriously."